The invention relates to a process, a device, and an installation using this device for the separation of gaseous components from pourable media, in particular suspensions of solids.
Processes and devices for the separation of gases from liquids, suspensions and solids-gas-mixtures known so far operate on the principle of a centrifuge. Here the medium to be separated from the gas must be set in rotation, the heavier components being enriched at longer radii because of stronger centrifugal forces and the gases and more volatile components mainly at shorter radii and at the center of rotation, respectively. The gas accumulated at shorter radii is then evacuated from the system via an appropriate conduit. In most cases underpressure is applied to the evacuating system for the removal of gas.
A disadvantage of such processes is that energy has to be introduced into the medium for generating swirl, which energy is completely or partly lost in the further course of the process.
A further disadvantage resides in the fact that complicated control is often necessary in order to avoid that a large amount of gas, in particular air, but no other components are separated. This applies in particular when varying amounts of gas occur in the medium to be degassed during operation.
Conventional processes are furthermore disadvantageous in that additional devices aiming at a stabilization of the spout-like gas separation are necessary for efficient operation.
With media and liquid-solids-gas-mixtures, respectively, as for instance the suspensions of fibrous material occurring in paper and pulp industry, the gaseous components (mostly air) adhere well to the fiber network, thus making the segregation of gaseous and non-gaseous components (water, fibers, etc.) more difficult. In these cases it is of major importance to keep the distance the gas has to travel inside the medium in order to reach the zone from where it may be evacuated as short as possible. The result thereof is that with known processes long dwelling times of the medium in the region of the centrifuge are necessary because of the long travel distances, and thus the throughput of the medium is strongly limited or the centrifuge becomes very long.
A further disadvantage of known processes and devices resides in the fact that, in order to prevent the concomitant separation of non-gaseous components, provision has to be made for devices functioning as a sieve. Especially with media likely to form clots, as for instance the fiber suspensions dominating the paper and pulp industry, the components carried along with the evacuated gas may result in clogging. Rinsing means are necessary in order to prevent this.